The Chlor-Alkali process is an industrial technology for the electrolysis of sodium chloride (NaCl) or potassium chloride (KCl). This technology is used to produce chlorine (Cl2), sodium hydroxide (NaOH, caustic soda) or potassium hydroxide (KOH, caustic potash) and hydrogen (H2), which are commodity chemicals required by industry.
Consito developed know-how and technologies for small scale chlor-alkali units, 1 to 15 MTPD chlorine capacity, in order to provide for a reliable, highly efficient device to produce "on site" chlorine, 32% caustic soda/caustic potash and hydrogen.
The availability on site of such products eliminates the risks associated with their transportation and storage especially in countries with high ambient temperature.
Our small scale plants, named CHLOR-PACK®, are pre-assembled, modular skid-mounted electrolysis units, based on bipolar membrane cells. They can be equipped with transformer-rectifier, brine preparation, brine purification, depleted brine dechlorination, automatic control.
Chlorine gas can be dried and compressed to be fed directly by pipeline to the consumers or liquefied under pressure and stored.
We can supply falling film evaporators for caustic soda/potash concentration up to 50% or to flakes.
Alternatively, chlorine and caustic soda can be directly converted to sodium hypochlorite ("bleach") in a further step of our plants or to hydrochloric acid.
CHLOR-PACK® is a pre-assembled, modular skid-mounted electrolysis unit, based on bipolar membrane cells, the most flexible and less expensive membrane electrolysis device, where the salt brine solution is transformed to chlorine, caustic soda and hydrogen, according to the following reaction:
Bipolar membrane cell is the main component of packaged, preassembled electrolyzers in small plants for production of caustic and chlorine from salt.
The cells can be assembled in a standard module in a wide range of arrangements. Moreover, each module can be equipped with its own rectifier, or, if the customer's requirements concerning the maximum circuit voltage are matched, it is also possible to get the required production arranging in series several modules fed from a single rectifier.
Our electrolysis units can includes the following stages:
Raw materials of the electrolysis are salt (NaCl or KCl) and water (H2O).
Sources of salt include sea water (solar salt NaCl), mineral deposits (rock salt NaCl or KCl) or salt produced by brine evaporation (vacuum salt NaCl or KCl).
Membrane grade caustic in the form of a 32 % NaOH solution or 29 % to 32 % KOH solution, hydrogen gas and chlorine gas are the primary products obtained in our CHLOR-PACK®.
| Production | ||
|---|---|---|
| Cl2 | MTPD | 1 to 15 |
| NaOH 32% (as 100%) | MTPD | 1.12 to 16.8 |
| Hydrogen | t/tCl2 | 0.028 |
| Single cell voltage | V | 3.5 |
| Operation amperage | kA/m2 | 4.0 |
| Current efficiency | % | 93 |
| Raw materials & utilities | ||
| Solar salt (NaCl 98%) | t/t Cl2 | 1.83 |
| HCl (32%) | kg/t Cl2 | 1.8 |
| Sodium bisulphite or H2O2 (dechlorination) | kg/t Cl2 | <10 |
| NaOH (32%) (precipitation) | kg/t Cl2 | 39 |
| Na2CO3 (precipitation) | kg/t Cl2 | 40 |
| Process water (caustic) | m3/t Cl2 | 1.03 |
| Process water (dissolving) | m3/t Cl2 | 1.73 |
| DC power | kWh/t Cl2 | 2,600 |
| Effluents | ||
| Liquors, sludge | kg/t Cl2 | 522 |
| Solids, sludge | kg/t Cl2 | 131 |
Large quantities of chlorine and caustic are required as key chemicals for a wide range of end products, for the following industries:
Beside the small scale chlor-alkali units, 3V Tech's Mabo Division designs and supplies tailor-made evaporation/crystallization plants for the chlor-alkali industry, also for large capacities, which can be arranged as skid-mounted units or suitable systems for on-site installation: